1. Technical Field
Embodiments described herein relate to a passenger-side airbag folded body for restraining an occupant on a passenger seat at the time of vehicle collision or the like, and in particular relates to a passenger-side airbag folded body in which an inflator opening is provided at a base end thereof in an inflation direction and a vent hole is provided at each of right and left side surfaces thereof. Furthermore, the embodiments relate to an airbag apparatus including the passenger-side airbag folded body.
2. Related Art
As a method for folding a passenger-side airbag for restraining an occupant on a passenger seat at the time of vehicle collision or the like, the following folding method is illustrated in FIGS. 3 and 4 of Japanese Unexamined Patent Application Publication No. 6-227353. In this method, after an airbag has been flatly spread out, right and left sides of the airbag are folded so that the airbag is formed into a vertically elongated band-like body, a lower portion of the band-like body is folded in a bellows-like manner or in a roll-like manner, and then an upper portion of the band-like body is folded in a bellows-like manner.
As a passenger-side airbag, an airbag is known which includes a right half airbag and a left half airbag, which are to be inflated toward the right front and left front of an occupant, respectively. These airbags are inflated by a common inflator. A method for folding such an airbag is disclosed in Japanese Unexamined Patent Application Publication No. 2007-45190.
According to this patent document No. 2007-45190, when the airbag is folded, each of the right half airbag and the left half airbag is first transversely placed, and is then spread flatly in vertical and longitudinal directions. Subsequently, the left half airbag is folded in a roll-like manner or in a bellows-like manner from upper and lower ends thereof toward a vertical center, and is thus formed into a strip-like folded body elongated in the longitudinal direction. Further, the right half airbag is also similarly folded in a roll-like manner or in a bellows-like manner from upper and lower ends thereof toward a vertical center, and is thus formed into a strip-like folded body elongated in the longitudinal direction. Then, the resulting right half airbag and left half airbag folded bodies are each folded so that its longitudinal length is reduced, thus providing a final block-like folded body.
At the time of vehicle collision, gas flows from the inflator into the airbag through an inflator opening provided at an airbag base end, and thus the gas flows into each of the right half airbag and the left half airbag from the airbag base end. As a result, the right half airbag and the left half airbag are inflated toward the right front and left front of an occupant, respectively, to receive the arms of the occupant. A vent hole is provided at each of a right lateral surface of the right half airbag and a left lateral surface of the left half airbag; thus, when the occupant comes into contact with the inflated right half airbag and left half airbag, the gas flows out of the airbag through each vent hole, thereby absorbing an impact applied to the occupant.
In the airbag folding method disclosed in Japanese Unexamined Patent Application Publication No. 6-227353, when the airbag is formed into an elongated band-like body as illustrated in FIG. 3, vent holes are folded into the airbag. Since the band-like body is further bellows-folded or roll-folded in this state, the vent holes are buried inside an airbag folded body. Therefore, in the method disclosed in this patent document, the vent holes will not be opened to the atmosphere until an inflator is activated and the airbag is inflated to a considerably large size, and thus gas will hardly flow out of the vent holes during this period of time.
Furthermore, in the folding method disclosed in Japanese Unexamined Patent Application Publication No. 2007-45190, when the right half airbag and the left half airbag are each folded in a roll-like manner or in a bellows-like manner from the upper and lower ends thereof toward the vertical center, panel portions of the right half airbag and the left half airbag are folded over the vent holes. Therefore, in the method disclosed in this patent document, even when the inflation of the airbag is started, gas is not allowed to sufficiently flow out of each vent hole until the vertical folding of the right half airbag and the left half airbag is unfolded.
In light of the above facts, the conventional passenger-side airbag has the following problem. When the airbag is inflated in a state where an object such as an occupant is present over an instrument panel or in the immediate vicinity thereof, the object comes into contact with the airbag before the airbag is sufficiently unfolded. Hence, even when the object is brought into contact with the airbag, gas might not be allowed to sufficiently flow out of each vent hole, and thus a force applied to the object from the airbag might be increased.